Lone star tick ( Amblyomma americanum)ĭistribution: Amblyomma americanum is widely distributed in the United States from Texas north to Missouri and eastward to the Atlantic coast (Figure 7). Notes: American dog ticks are much larger than blacklegged ticks and engorged female ticks may be the size of a grape. Dermacentor variablis do not vector the causative agent of Lyme disease. They have also been known to transmit tularemia and to cause canine tick paralysis. They can be extremely aggressive biters.ĭiseases: American dog ticks are main vector of the pathogens that cause Rocky Mountain spotted fever in Pennsylvania, which is less common than Lyme disease but a potentially more serious illness.
Adults are frequently found on dogs (hence the common name) but also feed on other medium and large mammals such squirrels, raccoons, rabbits, ground hogs, fox, deer, domestic livestock, and humans. Hosts: Larvae and nymphs prefer to feed on small rodents. However, unfed individuals of all life stages can survive for more than a year between hosts (larvae: 15 months nymphs: 20 months adults: 30 months), so all life stages may be encountered year-round. They prefer open locations with little or no tree cover, such as grassy fields and scrublands.Īctivity period: Larvae are most common during the spring and fall while nymphs and adults are found throughout the summer. American dog tick ( Dermacentor variabilis)ĭistribution: Dermacentor variabilis is found in the eastern two-thirds of the United States from Nova Scotia to the Gulf Coast, including all of Pennsylvania (Figure 5). However, because deer have been historically considered the preferred host only during the adult stage, blacklegged tick is the preferred common name. Note s: This tick is often called the "deer tick". In Pennsylvania, 20–40% of blacklegged ticks test positive for B. Because ticks need to feed from a host infected with pathogens to be able to transmit those pathogens to humans or other animals, only nymphs and adult ticks spread the pathogen. However, another pathogen, Powassan virus, can be transmitted in as little as 15 minutes. While there is still some debate, blacklegged ticks typically need to feed for 24 hours before Borrelia burgdorferi, the causative agent of Lyme disease, is transmitted. which can cause anaplasmosis and babesiosis, respectively. Larval ticks are typically present during the late summer and nymphs during the late spring and through the summer.ĭiseases: Blacklegged ticks are best known as the vector of the pathogens that cause Lyme disease but have also been known to vector other pathogens including Anaplasma spp. During the winter, adult ticks can be active and seek hosts any day when temperatures are above freezing. However, any stage is capable of feeding on humans, livestock, and companion animals.Īctivity period (Figure 3): Adult ticks are present in the fall, throughout the winter, and in early spring. Adult blacklegged ticks feed on larger mammals with some preference for white-tailed deer. Hosts: Blacklegged tick larvae preferentially feed on small mammals such as mice and chipmunks and occasionally birds nymphs also feed on small mammals and birds, as well as a range of medium- and large-mammals like raccoons, deer, and black bears. While it was less widespread historically, the range of this species has been expanding in recent years and it can now be found throughout Pennsylvania. Blacklegged tick ( Ixodes scapularis)ĭistribution: Ixodes scapularis is found throughout the eastern United States and in parts of the northern mid-west in wooded, brushy locations as well as grassy edge habitat (Figure 2). Three other species that may be encountered are also covered herein: lone star tick ( Amblyomma americanum), Asian longhorn tick ( Haemaphysalis longicornis), and winter tick ( Dermacentor albipictus).
Of these, two species account for more than 90 percent of identification requests submitted to Penn State: blacklegged tick ( Ixodes scapularis) and American dog tick ( Dermacentor variablis). There are more than 900 species of ticks worldwide, at least 25 of which occur in Pennsylvania. The most important of these in Pennsylvania are the bacteria that cause Lyme disease and Rocky Mountain spotted fever. Many species of ticks can transmit pathogens between animals and to humans, including various parasitic worms, viruses, and bacteria. Ticks are parasitic arthropods that feed on the blood of vertebrates, particularly mammals (including humans) but also birds, reptiles and amphibians.
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